The present invention relates generally to the utilization of ultrasonic sound waves to take dimensional measurements of objects and, more specifically, to a method and apparatus for ascertaining three-dimensional measurements and/or volume of objects.
It is known in the art to use sound waves to measure distances, thicknesses and even to generate holographic images. For example, U.S. Pat. No. 4,161,715 discloses an acoustic system for measuring the interior dimensions of a hollow body such as a cavern intersected by a wellbore. U.S. Pat. No. 4,748,846 discloses the use of ultrasound to determine the level of liquid, such as gasoline, in a storage tank; U.S. Pat. No. 4,601,207 employs ultrasonic means to measure the strain upon roof bolts in mines, stress effecting an elongation of the bolts which is determined from the increase in travel time of sound waves between locations on the bolts. U.S. Pat. No. 4,757,716 discloses a system for inspecting turbine and generator rotor bores using ultrasound, while U.S. Pat. No. 3,916,676 measures thickness of cable jackets using ultrasonic transducers placed about the outside of the cable. Ultrasonic location of a moveable object, for example a piston within a cylinder, is disclosed in U.S. Pat. No. 4,543,649, and in U.S. Pat. No. 4,029,176, acoustic waves are used to detect the presence of persons in a "zone of danger" between sliding doors, such as elevator doors, and prevent premature closing. U.S. Pat. Nos. 4,237,737, 4,409,839, 4,572,203, and 4,714,846 are each directed to aspects of ultrasonic imaging as it specifically pertains to medical applications.
While the above-noted patents utilize acoustic energy in various contexts involving dimensional measurement, there remains a void in the business world for a precise, rugged measurement system for inanimate objects.
For example, millions of packages per year are handled and shipped by United Parcel Service, Federal Express, and many other smaller courier and delivery services. These packages originate with federal, state, and local governments as well as private businesses of all sizes. In many instances, the charges by the carriers to their customers are based on the so-called "dim-weight factor" or "dimensional weight factor" (DWF) of the article being shipped, a fictitious dimension based on length times width times height in inches divided by a standard agency or association-recognized divisor or conversion factor, commonly 166 (L.times.W.times.H+166). The "166" divisor or conversion factor has been recognized and adopted by the International Air Transport Association (I.A.T.A). Even if an object or package is of irregular configuration, the dim weight, using the longest measurement each of length, width, and height, is still utilized for billing purposes.
The measurements of the articles shipped is also critical so that the carrier can accurately determine the number of trucks, trailers, or other vehicles which will be required to transport goods to their destinations and so both customers and carriers can accurately estimate their warehousing and other storage needs.
In addition, article weight and measurements are also used to determine and predict weight and balance for transport vehicles and aircraft and to dictate the loading sequence for objects by weight and dimensions for maximum safety and efficiency.
Further, if orders of any items are to be packed into boxes, knowledge of object weight and dimensions would be useful for selecting box size and durability.
To date, it has been a common practice for the customer to manually "cube" or measure boxes or other articles with a ruler, yardstick, or other straightedge marked with units of length, generally inches, perform a calculation for "dim weight," and provide same to the carrier with the package. If the customer does not "cube" the articles, then the carrier performs the operation. Since these measurements and calculations are generally done hurriedly, there is an equal chance that the customer will be under or over charged. To add to the problem, there are many packages and other objects not susceptible to even a grossly accurate manual measurement of dim weight, for example and not by way of limitation, loaded pallets, tubes, drums, reels of hose, cable or wire, etc. Many machine and automotive parts are shipped "naked" with tags attached or, at most, bagged or shrink wrapped. It is obvious to one skilled in the art that a straightedge measurement to ascertain the greatest extent of each dimension will not be accurate in any of these instances to any degree whatsoever.
It is known to the inventor that a "jig"-type measuring system for packages has been used, with a base and two sides joining in a corner at 90.degree. angles, each marked with gross dimensional units (to the nearest one inch) so that a cubic package can be placed on the base at the corner and measurements taken manually by looking at the markings and recording same, but again, the accuracy is limited by the care and eyesight of the measurer, and the time utilized is unreasonably long when thousands of packages are being shipped, as with Sears, K-Mart, or other large retailers.
In short, the prior art has not provided a quick, accurate means and method for measuring packages and other objects in a commercial or industrial setting.